Transient saturation absorption spectroscopy excited near the band gap at high excitation carrier density in GaAs
Wu Song-Jiang (吴松江)ab, Wang Dan-Ling (王丹翎)a, Jiang Hong-Bing (蒋红兵)a, Yang Hong (杨宏)a, Gong Qi-Huang (龚旗煌)ab, Ji Ya-Lin (季亚林)b, Lu Wei (陆卫)b
a State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, and Department of Physics, Peking University, Beijing 100871, China; b State Key Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
Abstract Transient saturation absorption spectroscopy in GaAs thin films was investigated using femtosecond pump and supercontinuum probe technique at excitation densities higher than $1\times10^{19}$cm$^{-3}$. The Coulomb enhancement factor of the electron－hole plasma results in a spectrum hole at the pump wavelength. Two distinct transmission peaks at two sides of the pump wavelength are observed, arising from the bleaching of transitions from the heavy- and light-hole bands to the conduction band. The dynamic process of the transient saturation absorption is fitted using a bi-exponential function. The fast decay process is dominated by the carrier-phonon scattering and the slow process may be attributed to the electron－hole recombination.
Received: 17 February 2003
Revised: 02 June 2003
Accepted manuscript online:
PACS:
73.50.Gr
(Charge carriers: generation, recombination, lifetime, trapping, mean free paths)
(Effects of atomic coherence on propagation, absorption, and Amplification of light; electromagnetically induced transparency and Absorption)
Fund: Project supported by the National Key Basic Research Special Foundation of China (Grant No G1999075207), and the National Natural Science Foundation of China (Grant Nos 90101027, 90206003 and 19884001).
Cite this article:
Wu Song-Jiang (吴松江), Wang Dan-Ling (王丹翎), Jiang Hong-Bing (蒋红兵), Yang Hong (杨宏), Gong Qi-Huang (龚旗煌), Ji Ya-Lin (季亚林), Lu Wei (陆卫) Transient saturation absorption spectroscopy excited near the band gap at high excitation carrier density in GaAs 2004 Chinese Physics 13 111
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